The invention relates to a rinsing tank for rinsing with ultra clean liquid comprising a rinsing chamber confined by an enclosure equipped at the bottom part with a diffusing device with a perforated base plate connected to a first pressurized liquid supply system, and with an overflow spout at the upper part to receive the rinsing liquid charged with particles or contaminants removed from the objects to be rinsed.
A first type of known rinsing tank operates by overflow due to the presence of an overflow pipe at the top part of the tank. The rinsing chamber is filled with ultra clean deionized water up to the level of the overflow pipe. Filling is performed by means of a water inlet pipe situated in the central part of the bottom of the tank. The water flows out by overflowing into the overflow pipe and is removed by an outlet pipe. Rinsing of the substrates contained in the container inside the rinsing chamber is achieved by a simple filling effect of the tank. FIG. 3 of the document U.S. Pat. No. 5,485,861 describes such a device which requires a large volume of deionized water. The turbulence effect created in the rinsing chamber when the water rises disturbs the uniform circulation of the water to the detriment of the cleaning characteristics.
A second type of known rinsing tank operates by fast draining due to the presence of a removable flap in the bottom of the tank. The tank is first filled with deionized water and is then drained by gravity after the removable flap has been opened. The high speed of the downward water flow washes away the contaminant elements present on the substrates. This type of tank also requires a large consumption of deionized water.
The document U.S. Pat. No. 5,485,861 shows a similar device in FIGS. 1 and 2, but removal of the water takes place via holes arranged in the bottom of the tank which is connected to the outlet pipe.
The object of the invention is to achieve rinsing tank for rinsing with an ultra clean liquid enabling optimum rinsing of the objects contained in the tank to be obtained with a small consumption of liquid.
The device according to the invention is characterized in that the rinsing chamber comprises in addition:
a plurality of projection nozzles or injectors connected to a second pressurized liquid supply system, said nozzles being distributed along the periphery of the perforated base plate of the diffusing device,
a deflector situated close to the overflow spout and having the form of a convergent to divert the rising flow coming from the nozzles to the central part of the rinsing chamber causing a downward circulation of liquid designed to remove the contaminants and particles,
and means for reversing the flow due to the hydraulic piston effect generated by the first supply system of the base plate which forces the rinsing liquid upwards towards the overflow spout.
According to one feature of the invention, the deflector constitutes the internal face of the overflow spout and the enclosure comprises at least two inclined side faces extending between the base plate and the deflector. The nozzles or injectors can advantageously be directed inside the rinsing chamber either in the direction of the side faces of the enclosure or in another predetermined direction.
According to another feature of the invention, the base plate of the diffusing device bears a diverting element to direct the descending flows in the direction of the sides of the enclosure. The diverting element is in the form of a divergent extending in the central part of the base plate, and presents a prismatic shape having a base resting on the base plate and a peak directed towards the objects to be rinsed.
The objects to be rinsed are constituted by substrates commonly encountered in the semi-conductor, micro-systems and flat screen industries, notably silicon-, AsGa-, germanium-, quartz-, or glass-based, or such like, which substrates being arranged in parallel manner in a container inside the rinsing chamber.
According to another feature of the invention, sonic antennas generate acoustic vibrations in the rinsing liquid.